In the ore mining industry rock containing ore fractions in the percentage range is extracted, from which a valuable material concentrate must be obtained. In the prior art this is effected in practice in a purely mechanical manner by way of what are known as floating aggregates. Magnetic separation is also proposed. In the case of magnetic separation within the context of ore extraction there exists the requirement to separate magnetizable particles, and where applicable agglomerates of magnetizable particles with mineral particles, in particular valuable ore particles, from other mineral particles which are contained in the same suspension (pulp) by means of magnetic fields. In particular it is required that this is done in a continuous process in order to manage the desired high mass flow rates of typically 1000 m3/h and more.
Magnet arrangements have already been described which allow a concentrated pulp stream, what is known as the concentrate, in which the magnetizable particles are present in high concentration, to be obtained in proximity to the wall of the magnet system of a tubular or gap-like separating reactor, which is generally called a separator. The depleted mass stream (tailing) flows in the remaining tube or gap volume, and accordingly the task is to separate this from the valuable material stream. Since both mass flow rate and particle concentrations may be subject to strong variations, the separation of concentrate and tailing must be able to compensate for correspondingly large variations in the partial mass streams.
Until now no continuously operating ore separation methods have existed in practice in which a corresponding separation of concentrate and tailing is performed. It is proposed to accomplish the separation through lateral extraction of the concentrate by way of a corresponding pipe socket, it being possible to influence the separation rate only by influencing the flow rate, for example by way of additional pumps or restriction of the volume flow. It is furthermore proposed that in a cylindrically symmetrical arrangement the separation of the concentrate and tailing material flows is performed by way of a tubular separating screen. In this case, however, the diameter of the separating screen generally cannot be changed, so the ratio of the concentrate-tailing flow rates can similarly only be influenced through control of the mass flow rate. It is therefore necessary to disclose a separating screen construction by means of which the ratio of the volume flow rates is easily and reliably controlled as a function of corresponding control variables so that the overall process always executes in an optimal manner.